Deflectors for fourdrinier forming wires



Nov. 27, 1962 E. D. BEACHLER ET AL 3,065,789

DEFLECTORS FOR FOURDRINIER FORMING WIRES Filed Sept. 21. 1959 22 V52? f571- 5 AL aUG/W Q Baac/er United States Patent 3,065,789 nnrrncrons nonronnnn FORMING winEs The present invention relates to paper machines,and more particularly to an improved drainage control anrangement in apaper machine to provide for a more precise control of the rate ofdrainage in a Fourdrinier machine.

The table rolls or tube rolls extend transversely beneath the formingwire and are designed to support the wire by forming a level table onwhich the wire runs after it passes beneath the slice. The rolls areordinarily supported for free rotation in bearings adjustably attachedat the side of the wire in suitable supporting members and are usuallyrotated by contact with the wire. The table rolls, in addition tosupporting the wire, carry 01f water or white water from beneath thesurface of the wire. A negative pressure and a pumping effect isexperienced at the outgoing nip between the roll and the Wire which isprimarily a function of the square of the wire speed. Especially in highspeed machines, the water removal function of the rolls is difficult tocontrol in that excessive pumping action may be experienced causing pinholes and loss of fine materials from the web. The table roll carryingwater on its surface may likewise damage the formation of the web by thegeneration of erratic upward forces on the web.

The instant invention resides in a discovery concerning the moreeffective control of water removal caused by the table rolls and theelimination of undesirable effects on the web on the wire from impropercontrol of water removal.

An object of the invention is to provide an improved table rollcombination for the controlled removal of water.

Another object of the instant invention is to provide an improved tableroll arrangement wherein controlled drainage will result in a better weband wherein the jump of paper stock on the Wire which causes pin holingand a loss of fines is eliminated.

A further object of the invention is to provide a smooth fully directedflow from a table roll into drainage trays which are also known assavealls.

A still further object of the invention is to provide a table rollarrangement wherein a deflector is mounted in a position to controldrainage from a table roll by limiting the pumping action of the highspeed roll and is provided with a deflector baflie to provide a drainagechannel on the downrunning side of the roll.

Another object of the invention is to provide an improved mechanism forremoving water carried around the table roll by providing anon-contacting blade to remove and split the water carried by the roll.

A still further object of the invention is to provide sep aratednon-diverging deflectors after a table roll with a deflector baflle toseparate the water removed ahead of the first deflector from the waterremoved between the deflectors.

A still further object of the invention is to provide an improved waterremoval control mechanism for a table roll which will not have excessivevibrations due to the pulsating effect of the water.

Other objects and advantages will become more apparent with the teachingof the principles of the invention in connection with the disclosure ofthe preferred embodi- 3,55,789 Patented Nov. 27, 1952 ment thereof inthe specification, claims and drawings, in which:

FIGURE 1 is a side elevational view shown in schematic form of the headend of the paper machine;

FIGURE 2 is a top plan view, enlarged from FIGURE 1, showing a series oftable rolls, with the Wire removed, and provided with apparatuscontrolling the removal of water by the rolls;

FIGURE 3 is a vertical sectional view taken substantially along the lineIlIlll of FIGURE 4, and,

FIGURE 4 is a vertical sectional view taken longitudinally through apaper machine and illustrating apparatus embodying the principles of thepresent invention.

As shown on the drawings:

As shown in FIGURE 1, a forming wire 6 carrying a stock S thereon passesover a series of table rolls 7, 8, 9 and 11 in the direction indicatedby the arrow, with the table rolls also shown in FIGURE 2. Followingeach of the rolls 7, 8 and 9 are water drainage control mechanisms 12,13 and 14, respectively, as will be described in further detail. Beneaththe drainage control mechanisms is a drainage collecting tray, alsoknown as a saveall 15. The forming Wire 6 is trained over a closed orplain breast roll 16 and a lower roll 17. Paper stock is supplied to thetraveling wire from a head box 18.

As illustrated in FIGURE 2, the table rolls 7, S, 9 and 11 are supportedin bearings mounted on longitudinal frame beams 19 and 21 of theFourdrinier bed. Bearings 22 are shown supporting the ends of the tableroll 7, with bearings 23, 24 and 26 respectively supporting the ends ofthe table rolls 8, 9 and ill. Following each of the rolls is a waterdrainage control mechanism as illustrated at l2, l3 and 14 for the tablerolls 7, 3 and 9.

As shown in greater detail in FIGURE 4, and also as shown in FIGURES l,2 and 3, each of the water drainage control mechanisms includes a firstdeflector 27, a second deflector 2.8, a deflector baflle 29, a lowerbaffle 31, a back bafiie 32., and a blade 33. The function and structureof each of these members in the preferred embodiment will be describedin greater detail, and as will be appreciated by those skilled in theart, and function and advantages of individual elements may be utilizedin different subcombinations without requiring all of the otherelements, although the preferred embodiment contemplates employment ofeach of the members above recited. inasmuch as each of the waterdrainage control mechanisms following each of the table rolls are ofsubstantially the same construction, only one need be described indetail and the control mechanism 12, as shown in FIGURE 4 will bedescribed.

An important feature of the invention is the placement of the elementsrelative to the table roll for obtaining controlled drainage. Asillustrated in FIGURE 4, the dimension A which represents the distancefrom the center 34 of the roll 7 to the leading edge 36 of the firstdeflector Z7 is critical. At high speeds especially, this dimension Amust be sufiiciently large to permit desired drainage and we havediscovered that with an inadequate dimension A, the reduction in watercapacity at this point i.e., in the throat area 37 between the deflector27 and roll 7, is a principal source of damaging vibrations of the web16.

The first deflector 27 has an upper flat surface 27a facing the undersurface of the wire 6 and extending at a non-divergent angle with thewire. That is, the surface 27a will not diverge from the Wire in thetrailing direction but will be at least parallel to the wire, and may,in some occasions, be inclined to form a converging angle.

The critical nature of dimension A results from the previously mentionednegative pressure present in the area of the outgoing nip 3%; which isan approximate function of the square of the wire speed. With the highspeeds s eaves encountered in modern paper machinery very high degreesof suction are created. This removes the water too fast from the webwith a consequent loss of fines and fibers. This suction effect alsocauses the wire to deflect and to wrap the table roll slightly which inturn extends the problem in that the time during which the suctionoperates tends to cause even further water removal. Under theseconditions there is also caused at the table roll a spray of stock whichjumps upward from the main stock stream damaging the web both where itleaves the stream and where it falls back onto the web. The causes ofthis phenomenon are not completely understood. On the other hand effortsto bring wire supporting means into this area, thereby reducing thedimension A below its critical minimum, inhibit water removal. Suchconstructions also provide insufiicient strength both for the edge ofthe deflector and for its stiffness as a beam transverse to theFourdrinier. The pulsating effect of such water as is removed then setsup damaging vibrations in the deflector means. Furthermore, thedifficulty of adjusting such deflector means may tend to lift the wirethus tending in turn to stall the rotation of the roll.

If the dimension A is too large or if the deflector 27 is elevated abovethe plane established by the top surfaces of the table rolls anexcessive drag on the stationary surface results. Whether this resultsfrom the curvature of the wire span or from the weight of the wireitself the web is also damaged by the disturbance created in the stock.

The actual dimension A depends principally on speed and wire tension, aswell as on the character of the stock being formed and the particularposition in the sequence of table rolls being used. In a particularpaper machine trial settings provide a precise control of the rate ofdrainage and permit the rapid smooth removal of water without choking orother disturbance in the channel 37.

Because of the action of the table roll- 7, the principal water removaltakes place between the roll and the top deflector surface 27a. Drainageto some extent takes place in the channel 39 provided between the firstdefiector 27 and the second deflector 23. The second deflector 28 has anupper surface 28a which is preferably parallel to the under surface ofthe wire 6 and forms a non-diverging angle therewith, that is, the uppersurface 2811 can form a converging angle or be inclined with respect tothe direction of travel of the wire as shown by the arrow.

The drainage through the channel 37 and the drainage through the channel39 combine below the deflector baffle 29 to be deflected downwardly bythe back baflle 32 and to drop down on the lower baffle 31 and flow downinto the saveall 15.

The baflie 31 directs the large volume of water removed by the drainageapparatus 12 into the saveall trays 15 with a minimum of disturbancethus permitting the total flow in the tray to move expeditiously towardits outlet. Without such provision the Water falling from the particulardeflector might dam up the flow of water in the saveall in turn causingit to overflow onto the return reach of the Fourdrinier wire to damageor destroy it.

A quantity of water will adhere by surface tension to the table roll 7.The blade 33 has a leading edge 33a facing the downrunning side of thetable roll and positioned closely to the surface of the table roll butnot in engagement therewith. The blade 33 splits the water following theroll and the principal part of the water is diverted to the outersurface 33b of the blade downwardly against the lower baffle 31. Anadditional amount of water is removed on the inner surface 33c of theblade which to some extent creates a pumping action due to the vacuumcreated between the blade and the roll 7. This water also flowsdownwardly against the lower bathe 31 and down into the saveall 15.

The blade 33 reduces to a minimum the water carried by the roll but doesso with very little loss of energy as might be the case if the bladewere in contact with the roll surface. Since the roll is turned byfriction with the wire it is essential that its rotation not beexcessively retarded.

The deflectors 27 and 28, the baffles 29, 31 and 32, and the blade 33form lateral beams extending across the machine and are secured at theirends to the longitudinal frame beams of the Fourdrinier bed withprovision for precise adjustment of elevation. The back baffle 32 has anangular upper portion 32a which supports the second deflector andtogether these elements form a laterally extending strengthening beam tobe attached at its ends to the longitudinal frame beams 19 and 21. Thedeflector 27 is also supported at the upper end of the deflector baffle29, and the baffles and deflectors are secured at their ends to theframe beams 19 and 21.

The water that is removed from the web is withdrawn with a pulsatingmotion so that the bafiles may vibrate. To aid in strengthening thebaffles and enable them to retain their shape and stiffness, a series oftransverse gusset plates 42 are provided, as illustrated in FIGURES 2, 3and 4.

Thus will be seen that we have provided an improved mechanism forcontrollably removing water from a Fourdrinier wire and a table roll,which meets the objectives and advantages hereinbefore set forth. Themechanism avoids excessive pumping at the table roll, removes themoisture from the surface of the table roll, and achieves an improvedmoisture removal by control of the moisture removal operation of theroll utilizing deflectors and baflles.

A control of the pumping action of the roll is obtained by the combineddeflectors and additional regulation of the roll may be obtained bymaking the deflector 27 and its deflector baflie 29 adjustable parallelto the direction of movement of the wire in the direction indicated bythe arrows 43. This adjustment may be accomplished by mounting the beamformed by the combination of the deflector 27 and deflector balfle 29 onan adjustable mount (not shown) at the end.

The drawings and specification present a detailed disclosure of thepreferred embodiments of the invention, and it is to be understood thatthe invention is not limited to the specific forms disclosed, but coversall modifications, changes and alternative constructions and methodsfalling within the scope of the principles taught by the invention.

I claim as my invention:

1. In a paper machine, a traveling forming wire for carrying stockthereon, first and second longitudinally spaced table rolls supportingthe forming wire, a drainage control device mounted between said rollsand extending for the length thereof and comprising, longitudinallyspaced first and second deflectors spaced in the direction of travel ofthe wire and having top wiping surfaces spaced from said rolls havingwiping contact with the wire between said rolls, a vertical drainageduct leading downwardly from said deflectors in the space therebetweenand having a back bafiie connected to and leading downwardly from saidsecond deflector along and beneath said second roll, said firstdeflector having a baflie connected thereto and extending angularlydownwardly therefrom into said drainage duct, a blade spaced downwardlyfrom said last mentioned baflie having an edge extending along saidfirst roll, closely adjacent but free from said first roll to split anddirect the water on said roll into said duct, said blade with said lastmentioned baflle defining a diverging throat opening to said duct, andvertical laterally spaced stiffness plates extending at spaced intervalsacross said drainage control device between said blade and said backbaflle and rigidly attached thereto.

2. In a paper machine, a traveling forming wire for carrying stockthereon, first and second longitudinally spaced table rolls supportingthe forming wire, a drainage control device mounted between said rollsand extending ,5 for the length thereof and comprising, longitudinallyspaced first and second deflectors spaced in the direction of travel ofthewire and having top wiping surfaces spaced from said rolls havingwiping contact with the Wire in the space between said rolls, a verticaldrainage duct leading downwardly between said deflectors and having aback baffle connected to and leading downwardly from said seconddeflector along and beneath said second roll, a lower angularlyextending baffle inclined to face upwardly toward said back baflfle andto deflect the water removed from the wire in the direction of travel ofthe wire, said first deflector having a baffle connected thereto andextending angularly downwardly therefrom into said drainage duct, ablade spaced downwardly from said last mentioned bafile having an edgeclosely adjacent but free from said first roll to split and direct thewater on said roll into said duct, said blade with said last mentionedbaffle defining a diverging throat opening into said duct and of greatercapacity when the volume of water said blade and said baflles to preventvibration of said blade and said baflles by the action of the waterthereon.

References Cited in the file of this patent UNITED STATES PATENTS1,748,06-2 Cofrin Feb. 25, 1930 1,781,928 Liebeck Nov. 18, 19302,170,109 Berry Aug. 22, 1939 2,225,435 Kellett et al. Dec. 17, 19402,694,345 Hornbostel Nov. 16, 1954 2,858,746 Goodwillie Nov. 4, 19582,893,486 Marti July 7, 1959 2,900,023 Hornbostel Aug. 18, 1959

